Reverse-DNS Resolution on Wifi Network with DHCP dynamic IP
We have some strange slow ssh logins on our internal servers, and I decided this morning to have a look at that.
I found out that the problem had to do with reverse-dns resolution for IPs served by our DHCP Server (the one included in pfSense 2.0.1). We use the DNS Forwarder module, and all options are enabled:
- Register DHCP leases in DNS forwarder
- Register DHCP static mappings in DNS forwarder
- Resolve DHCP mappings first
But even with that, all IPs served by the DHCP server cannot be reversed. And this is the cause of the slow ssh logins we have.
One way to correct that is to add a static DHCP mapping for my MAC address. Then reverse-dns resolution works, and of course then ssh logins are super-fast.
Is there some config I missed somewhere maybe? Or is that a small bug corrected in pfSense 2.0.2 / 2.0.3 maybe? I definitely have to update it as soon as possible…